Optical multi-wavelength dual-polarization transceivers

Abstract

A multi-wavelength dual-polarization (DP) receiver includes an input port configured to receive input light; an optical polarization splitter and rotator configured to split the input light into a first optical waveguide and a second optical waveguide; a first wavelength demultiplexer connected to the first optical waveguide and configured to output wavelength-demultiplexed light into a first plurality of optical waveguides; a second wavelength demultiplexer connected to the second optical waveguide and configured to output wavelength-demultiplexed light into a second plurality of optical waveguides; and a plurality of optical multi-input-multi-output (MIMO) polarization demultiplexers, each of which is connected to a respective one of the first plurality of optical waveguides and one of the second plurality of optical waveguides.

What is claimed is: 
     
         1 . A multi-wavelength dual-polarization (DP) receiver comprising:
 an input port configured to receive input light;   an optical polarization splitter and rotator configured to split the input light into a first optical waveguide and a second optical waveguide;   a first wavelength demultiplexer connected to the first optical waveguide and configured to output wavelength-demultiplexed light into a first plurality of optical waveguides;   a second wavelength demultiplexer connected to the second optical waveguide and configured to output wavelength-demultiplexed light into a second plurality of optical waveguides; and   a plurality of optical multi-input-multi-output (MIMO) polarization demultiplexers, each of which is connected to a respective one of the first plurality of optical waveguides and one of the second plurality of optical waveguides.   
     
     
         2 . The multi-wavelength DP receiver of  claim 1 , further comprising at least one variable optical attenuator (VOA) connected to the outputs of the first wavelength demultiplexer and/or the second wavelength demultiplexer. 
     
     
         3 . The multi-wavelength DP receiver of  claim 1 , wherein the optical polarization splitter and rotator, the first and second wavelength demultiplexers, and the plurality of optical MIMO polarization demultiplexers are all implemented on the same chip. 
     
     
         4 . The multi-wavelength DP receiver of  claim 3 , wherein the chip has a silicon substrate. 
     
     
         5 . The multi-wavelength DP receiver of  claim 1 , wherein, for each wavelength channel, the two path lengths from the input port to inputs of the plurality of optical MIMO polarization demultiplexers are within 0.2 mm of each other. 
     
     
         6 . The multi-wavelength DP receiver of  claim 1 , wherein the multi-wavelength DP receiver is co-packaged with a digital-signal processor. 
     
     
         7 . The multi-wavelength DP receiver of  claim 1 , further comprising taps and monitor photodiodes that are implemented on outputs of at least one of the plurality of optical MIMO polarization demultiplexers. 
     
     
         8 . The multi-wavelength DP receiver of  claim 1 , wherein the first and second wavelength demultiplexers have wavelengths that are electronically adjustable. 
     
     
         9 . The multi-wavelength DP receiver of  claim 3 , further comprising a transimpedance amplifier that is integrated into the chip. 
     
     
         10 . The multi-wavelength DP receiver of  claim 3 , wherein electronic control for the plurality of optical MIMO polarization demultiplexers is integrated into the chip. 
     
     
         11 . The multi-wavelength DP receiver of  claim 3 , further comprising a Stokes measurement apparatus that is integrated on the same chip. 
     
     
         12 . The multi-wavelength DP receiver of  claim 1 , wherein the first wavelength demultiplexer outputs a first plurality of wavelength-demultiplexed light signals of N wavelengths into the first plurality of optical waveguides,
 wherein the second wavelength demultiplexer outputs a second plurality of wavelength-demultiplexed light signals of the N wavelengths into the second plurality of optical waveguides, and   wherein an ordering of the N wavelengths for the first plurality of wavelength-demultiplexed light signals that are output from the first wavelength demultiplexer and an ordering of the N wavelengths for the second plurality of wavelength-demultiplexed light signals that are output from the second wavelength demultiplexer are in an opposite order.   
     
     
         13 . The multi-wavelength DP receiver of  claim 12 , wherein at least one of the N wavelengths has no waveguide crossings among the first plurality of optical waveguides and the second plurality of optical waveguides. 
     
     
         14 . The multi-wavelength DP receiver of  claim 1 , further comprising a plurality of photodetectors connected to respective outputs of the plurality of optical MIMO polarization demultiplexers. 
     
     
         15 . A multi-wavelength dual-polarization (DP) receiver comprising:
 an input port configured to receive input light;   an optical polarization splitter and rotator configured to split the input light into a first optical waveguide and a second optical waveguide;   a serial wavelength demultiplexer connected to the first optical waveguide and to the second optical waveguide and configured to output wavelength-demultiplexed light into a plurality of optical waveguides;   a plurality of optical multi-input-multi-output (MIMO) polarization demultiplexers connected to the plurality of optical waveguides; and   a plurality of photodetectors connected to respective outputs of the plurality of optical MIMO polarization demultiplexers.   
     
     
         16 . A method of receiving a multi-wavelength dual-polarization (DP) signal, the method comprising:
 performing polarization splitting on the multi-wavelength DP signal to generate a first optical signal and a second optical signal;   performing wavelength-demultiplexing on the first optical signal and the second optical signal to generate a plurality of wavelength-demultiplexed optical signals;   performing differential attenuation on the plurality of wavelength-demultiplexed optical signals; and   performing polarization demultiplexing on the differentially attenuated plurality of wavelength-demultiplexed optical signals.   
     
     
         17 . A multi-wavelength dual polarization (DP) transmitter comprising two lasers with a wavelength difference that is less than 15 nm. 
     
     
         18 . The multi-wavelength DP transmitter of  claim 17 , wherein the two lasers are electro-ab sorption-modulated lasers (EMLs). 
     
     
         19 . The multi-wavelength DP transmitter of  claim 17 , further comprising a polarization combiner that is configured to combine outputs of the two lasers. 
     
     
         20 . A multi-wavelength dual polarization (DP) transmitter comprising:
 a plurality of lasers, wherein the output of each laser is split into a pair of waveguides;   a plurality of pairs of DP modulators, wherein each pair of DP modulators consists of a first modulator and a second modulator that receive a respective pair of waveguides that are split from a respective laser among the plurality of lasers;   a first wavelength multiplexer with a plurality of inputs that are connected to outputs of the first modulators in the plurality of pairs of DP modulators;   a second wavelength multiplexer with a plurality of inputs that are connected to outputs of the second modulators in the plurality of pairs of DP modulators; and   an optical polarization splitter and rotator with (i) a first input that is connected to an output of the first wavelength multiplexer and (ii) a second input that is connected to an output of the second wavelength multiplexer.